#include<bits/stdc++.h>
#define fi first
#define se second
#define pitem item*
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<ll> vl;
const int N=1e6+10;
const int SS=1<<19;
const int INFi=2e9;
const ll INFl=1e16;
const ll mod2=998244353;
const ll mod=1e9+7;
const ll mod3=2027865967;
const ll p=70032301;
const ull p2=913;
const int L=20;
int n;
ll t[N];
void solve(){
cin>>n;
for(int i=1;i<=n;i++){
int a,b;
cin>>a>>b;
t[i]=t[i-1]+a-b;
}
multiset<ll> c;
c.insert(0);
ll res=0;
for(int i=1;i<n;i++){
auto it=c.end();
it--;
ll val=t[i];
if(t[i]<0) res+=abs(t[i]),val=0;
if((*it)>t[i]){
c.erase(it);
res+=(*it)-val;
c.insert(val),c.insert(val);
}else c.insert(val);
}
auto it2=c.end();
it2--;
auto it=c.end();
ll sl=0,pop=0;
for(it--;(*it)>t[n];it--,sl++){
res+=sl*(pop-*it);
pop=*it;
}
res+=sl*(pop-t[n]);
cout<<res<<"\n";
}
int main(){
ios_base::sync_with_stdio(0),cin.tie(0);
int tt=1;
while(tt--) solve();
}
